Add files via upload

java-csv/build.gradle

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+apply plugin: 'java'
+
+sourceCompatibility = 1.8
+targetCompatibility = 1.8

java-csv/csv.csv

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+SURNAME,MIDDLENAME,EMAIL,NAME,AGE
+Scarry,Noname,null,Jason,16
+Krueger,,[email protected],Fred,Unknown
+Scarry,Noname,[email protected],Jason,16

java-csv/csv1.csv

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+NAME,MIDDLENAME,SURNAME,AGE
+Jason,Noname,Scarry,16

java-csv/csv2.csv

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+MIDDLENAME,NAME,AGE,SURNAME,EMAIL
+,Fred,Unknown,Krueger,[email protected]
+Noname,Jason,16,Scarry,[email protected]

java-csv/src/main/java/com/jeejava/csv/CsvApplication.java

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+package com.jeejava.csv;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import com.jeejava.csv.parser.CsvParser;
+import com.jeejava.csv.vo.CsvVo;
+
+public class CsvApplication {
+
+ public static void main(String[] args) throws IOException {
+ File csv1 = new File("C:/csv/csv1.csv");
+ File csv2 = new File("C:/csv/csv2.csv");
+
+ List<String> csv1Headers = CsvParser.getHeadersFromACsv(csv1);
+ //csv1Headers.forEach(h -> System.out.print(h + " "));
+ //System.out.println();
+ List<String> csv2Headers = CsvParser.getHeadersFromACsv(csv2);
+ //csv2Headers.forEach(h -> System.out.print(h + " "));
+ //System.out.println();
+
+ List<String> allCsvHeaders = new ArrayList<>();
+ allCsvHeaders.addAll(csv1Headers);
+ allCsvHeaders.addAll(csv2Headers);
+ //allCsvHeaders.forEach(h -> System.out.print(h + " "));
+ //System.out.println();
+
+ Set<String> uniqueHeaders = new HashSet<>(allCsvHeaders);
+ //uniqueHeaders.forEach(h -> System.out.print(h + " "));
+ //System.out.println();
+
+ List<CsvVo> csv1Records = CsvParser.getRecodrsFromACsv(csv1, csv1Headers);
+ List<CsvVo> csv2Records = CsvParser.getRecodrsFromACsv(csv2, csv2Headers);
+
+ List<CsvVo> allCsvRecords = new ArrayList<>();
+ allCsvRecords.addAll(csv1Records);
+ allCsvRecords.addAll(csv2Records);
+
+ CsvParser.writeToCsv(new File("C:/csv/csv.csv"), uniqueHeaders, allCsvRecords);
+ }
+
+}

java-csv/src/main/java/com/jeejava/csv/parser/CsvParser.java

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+package com.jeejava.csv.parser;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Set;
+
+import com.jeejava.csv.vo.CsvVo;
+
+public class CsvParser {
+
+ public static List<CsvVo> getRecodrsFromACsv(File file, List<String> keys) throws IOException {
+ BufferedReader br = new BufferedReader(new FileReader(file));
+ List<CsvVo> records = new ArrayList<>();
+ boolean isHeader = true;
+
+ String line = null;
+ while ((line = br.readLine()) != null) {
+ if (isHeader) {// first line is header
+ isHeader = false;
+ continue;
+ }
+ CsvVo record = new CsvVo(file.getName());
+ String[] lineSplit = line.split(",");
+ for (int i = 0; i < lineSplit.length; i++) {
+ record.put(keys.get(i), lineSplit[i]);
+ }
+ records.add(record);
+ }
+
+ br.close();
+
+ return records;
+ }
+
+ public static List<String> getHeadersFromACsv(File file) throws IOException {
+ BufferedReader br = new BufferedReader(new FileReader(file));
+ List<String> headers = null;
+
+ String line = null;
+ while ((line = br.readLine()) != null) {
+ String[] lineSplit = line.split(",");
+ headers = new ArrayList<>(Arrays.asList(lineSplit));
+ break;
+ }
+
+ br.close();
+
+ return headers;
+ }
+
+ public static void writeToCsv(final File file, final Set<String> headers, final List<CsvVo> records)
+ throws IOException {
+ FileWriter csvWriter = new FileWriter(file);
+
+ // write headers
+ String sep = "";
+ String[] headersArr = headers.toArray(new String[headers.size()]);
+ for (String header : headersArr) {
+ csvWriter.append(sep);
+ csvWriter.append(header);
+ sep = ",";
+ }
+
+ csvWriter.append("\n");
+
+ // write records at each line
+ for (CsvVo record : records) {
+ sep = "";
+ for (int i = 0; i < headersArr.length; i++) {
+ csvWriter.append(sep);
+ csvWriter.append(record.get(headersArr[i]));
+ sep = ",";
+ }
+ csvWriter.append("\n");
+ }
+
+ csvWriter.flush();
+ csvWriter.close();
+ }
+}

java-csv/src/main/java/com/jeejava/csv/vo/CsvVo.java

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+package com.jeejava.csv.vo;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+public class CsvVo {
+
+ private Map<String, String> keyVal;
+
+ public CsvVo(String id) {
+ keyVal = new LinkedHashMap<>();// you may also use HashMap if you don't need to keep order
+ }
+
+ public Map<String, String> getKeyVal() {
+ return keyVal;
+ }
+
+ public void setKeyVal(Map<String, String> keyVal) {
+ this.keyVal = keyVal;
+ }
+
+ public void put(String key, String val) {
+ keyVal.put(key, val);
+ }
+
+ public String get(String key) {
+ return keyVal.get(key);
+ }
+
+}